I am highly motivated by the ‘HaBa’ blog and the ‘Haba’s Houses of Holland’ design (tutorial in English is available). I suppose that this project was provided for a small child, but in my opinions to the older will fit well too. Using a detailed information you can easily make your own bookshelf out of an old ladder and use pallets to make a beautiful row of dutch houses. Everything is up to you how you arrange empty wall.
There are a lot D.I.Y. pallet projects direct for kids, like the Toddler Pallet Bed. I’m sure that it will help you find the perfect inspiration.
Check out the full tutorial on the Haba’s Houses of Holland!